The decomposition of simple chlorinated organic compounds comprising benzene derivatives (mono, di and tri-chlorobenzenes) as the imitation substance of polychlorobiphenyls (PCBs) was investigated by using basic molten salts in order to establish a safe, simple and highly efficient decomposition process for PCBs. Chlorobenzen liquid or the solution was injected into basic molten salts (KOH–K₂CO₃ or NaOH–Na₂CO₃) at 573–973 K with imitation air, and the residual concentration of chlorobenzenes in the exhaust was measured after the decomposition treatment. The decomposition efficiency reached to very high of 99.9999% in an optimum condition. The decomposition efficiencies of chlorobenzenes were affected by the flow rate of the air and the initial concentration of chlorobenzen in the gas mixture. The complete destruction for benzene derivatives required excess oxygen condition.